<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../react18/react.development.js"></script>
  <script src="../react18/react-dom.development.js"></script>
  <script src="../react18/babel.min.js"></script>
  <script src="../react18/prop-types.js"></script>

</head>

<body>
  <div id="app"></div>
  <script type="text/babel">
    /* 
    如果发生事件的时候,需要获取自身元素的时候,可以直接使用e.target
 
  */

    class Parent extends React.Component {
      iptEle = React.createRef();
      render() {
        return (
          <div>
            <input type="text" ref={this.iptEle} />
            <button onClick={this.handle}>改变</button>

            <input type="text" onChange={this.iptChangeHandle} placeholder="表单修改后弹出输入的内容" />
          </div>

        )
      }
      handle = () => {
        const { value } = this.iptEle.current
        alert(value)
      }
      iptChangeHandle = (e) => {
        alert(e.target.value);
      }
    }

    const root = ReactDOM.createRoot(document.getElementById('app'));
    root.render(<Parent />)

  </script>
</body>

</html>